Surprisingly, for patients hospitalized with acute heart failure, a higher body mass index (BMI) was associated with a substantially lower death rate.

For every 5-unit increase in body mass, according to a new study, the odds of risk-adjusted mortality fell 10 percent. This finding held when adjusted for age, sex, blood urea nitrogen, blood pressure and other factors.

‘...[O]verweight and obese patients may have a greater metabolic reserve to call upon during an acute heart failure episode, which may lessen in−hospital mortality risk...’

While this study confirms a known phenomenon in chronic heart failure called the 'obesity paradox,' it is the first to document that this inverse relationship with BMI holds in the setting of acute hospitalization for heart failure. It suggests that the increased nutritional and metabolic support of higher body mass may somehow help patients recover from heart failure.

Authored by Dr. Gregg C. Fonarow, professor at the David Geffen School of Medicine at UCLA, the research appears in the January 2007 edition of the American Heart Journal.

"The study suggests that overweight and obese patients may have a greater metabolic reserve to call upon during an acute heart failure episode, which may lessen in-hospital mortality risk," said Fonarow.

Obesity is a known risk factor for developing heart disease and heart failure and, obviously, every effort should be made to avoid it, but once heart failure has occurred, this paradox seems to hold.

Researchers looked at data from over 100,000 separate cases of acute heart failure.